This project provides a mechanism for the development of information in the areas of environmental and occupational cancer and consists of four tasks. Task I is used to support NCI's Division of Cancer Etiology's Chemical Selection Working Group in its effort to select and nominate chemicals to the National Toxicology Program for carcinogenicity bioassay. The Division of Cancer Etiology, NCI, has been, and will continue to be, the primary source for nomination of candidate chemicals. Under Task I, class studies (chemicals by use or structural class) are conducted. From such class studies and other sources (IARC monographs, ad hoc nominations, in vitro studies, etc.) chemicals are selected and summary sheets are prepared to permit systematic evaluation and selection of candidates by the Chemical Selection Working Group. Task II of this project supports the information needs of the International Agency for Research on Cancer (IARC) by providing information for inclusion in Sections 1 and 2 of the IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. An average of three IARC working group meetings are held each year in Lyon, France, and a contractor representative is usually required to attend these meetings. Task III deals with the maintenance and updating of NCI's Chemical Carcinogenesis Research Information System (CCRIS). CCRIS is a scientifically evaluated and fully referenced data base containing carcinogenicity, tumor promotion, co-carcinogenicity, mutagenicity and, more recently, tumor inhibitor test results. Future expansion of this data base envisions the addition of an epidemiology file. This file is not intended to stand by itself but rather serve as a cross-linkage on specific compounds between the various files in CCRIS. Data to be included in CCRIS are evaluated by contractor, in consort with consultants, according to established criteria provided by NCI. CCRIS is resident and searchable in the National Library of Medicine's TOXNET system. Under Task IV, special studies have been prepared such as Speciesto-Species Comparison of Carcinogen Metabolism, Survey of Organic Drinking Water Contaminants, Inhibitors of Chemical Carcinogens, amongst others. To assure high quality of any state-of-the-art reports prepared under this task, such reports have been reviewed by consultants from within and outside the Federal government. Preparation of such reports will depend on availability of funding. Also under this task, the Bioassay Report Summary Handbook are being compiled and updated. This handbook now contains summaries of over 300 NCI/NTP Carcinogenesis Bioassay Technical Reports.